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Finding the Fourth Proportional to 497.72, 686.72 and 311.40

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Solution

The fourth proportional to 497.72, 686.72 and 311.40 is: 429.65

Step by Step Solution

  1. Step 1: Write the proportion equation
    497.72 : 686.72 = 311.40 : x
  2. Step 2: Convert to fraction form
    497.72/686.72 = 311.40/x
  3. Step 3: Cross multiply
    497.72x = 686.72 × 311.40
  4. Step 4: Simplify right side
    497.72x = 213,843.05
  5. Step 5: Solve for x
    x = 213,843.05/497.72
  6. Step 6: Final answer
    x = 429.65

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.